<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>透明度</title>
    <style>
        div{
            width: 500px;
            height: 500px;
            background-color: palegreen;
            opacity: 0;
            opacity: 1;
            opacity: 0.5n;
        }
    </style>
</head>
<body>
    <div>
        <img src="./imges/phone.png" alt="">
    </div>
</body>
</html>